Regex for “AND NOT” operation

I’m looking for a general regex construct to match everything in pattern x EXCEPT matches to pattern y. This is hard to explain both completely and concisely…see Material Nonimplication for a formal definition. For example, match any word character (\w) EXCEPT ‘p’. Note I’m subtracting a small set (the letter ‘p’) from a larger set … Read more

Multiple OR or AND conditions in IF statement

According to the C++ Standard 1 The && operator groups left-to-right. The operands are both contextually converted to bool (Clause 4). The result is true if both operands are true and false otherwise. Unlike &, && guarantees left-to-right evaluation: the second operand is not evaluated if the first operand is false. and 1 The || operator groups left-to-right. … Read more

Simple logical operators in Bash

What you’ve written actually almost works (it would work if all the variables were numbers), but it’s not an idiomatic way at all. (…) parentheses indicate a subshell. What’s inside them isn’t an expression like in many other languages. It’s a list of commands (just like outside parentheses). These commands are executed in a separate subprocess, so … Read more